SQLite

/*
** A segment of size nByte bytes has just been written to absolute level
** iAbsLevel. Promote any segments that should be promoted as a result.
*/
static int fts3PromoteSegments(
  Fts3Table *p,                   /* FTS table handle */
  sqlite3_int64 iAbsLevel,        /* Absolute level just updated */
  sqlite3_int64 nByte             /* Size of new segment at iAbsLevel */
){
  int rc = SQLITE_OK;
  sqlite3_stmt *pRange;

  rc = fts3SqlStmt(p, SQL_SELECT_LEVEL_RANGE2, &pRange, 0);

  if( rc==SQLITE_OK ){
    int bOk = 0;
    i64 iLast = (iAbsLevel/FTS3_SEGDIR_MAXLEVEL + 1) * FTS3_SEGDIR_MAXLEVEL - 1;
    i64 nLimit = (nByte*3)/2;

    /* Loop through all entries in the %_segdir table corresponding to 
    ** segments in this index on levels greater than iAbsLevel. If there is
    ** at least one such segment, and it is possible to determine that all 
    ** such segments are smaller than nLimit bytes in size, they will be 
    ** promoted to level iAbsLevel.  */
    sqlite3_bind_int64(pRange, 1, iAbsLevel+1);
    sqlite3_bind_int64(pRange, 2, iLast);
    while( SQLITE_ROW==sqlite3_step(pRange) ){
      i64 nSize, dummy;
      fts3ReadEndBlockField(pRange, 2, &dummy, &nSize);
      if( nSize<=0 || nSize>nLimit ){
        /* If nSize==0, then the %_segdir.end_block field does not not 
        ** contain a size value. This happens if it was written by an
        ** old version of FTS. In this case it is not possible to determine

        ** updated it to set (level = -1) and (idx = N), where N is 0 for the
        ** oldest segment in the range, 1 for the next oldest, and so on.
        **
        ** In other words, move all segments being promoted to level -1,
        ** setting the "idx" fields as appropriate to keep them in the same
        ** order. The contents of level -1 (which is never used, except
        ** transiently here), will be moved back to level iAbsLevel below.  */
        sqlite3_bind_int64(pRange, 1, iAbsLevel);
        while( SQLITE_ROW==sqlite3_step(pRange) ){
          sqlite3_bind_int(pUpdate1, 1, iIdx++);
          sqlite3_bind_int(pUpdate1, 2, sqlite3_column_int(pRange, 0));
          sqlite3_bind_int(pUpdate1, 3, sqlite3_column_int(pRange, 1));
          sqlite3_step(pUpdate1);
          rc = sqlite3_reset(pUpdate1);
          if( rc!=SQLITE_OK ){
            sqlite3_reset(pRange);
            break;
          }
        }
      }
      if( rc==SQLITE_OK ){
        rc = sqlite3_reset(pRange);
      }

      /* Move level -1 to level iAbsLevel */
      if( rc==SQLITE_OK ){
        sqlite3_bind_int64(pUpdate2, 1, iAbsLevel);
        sqlite3_step(pUpdate2);
        rc = sqlite3_reset(pUpdate2);
      }
    }
  }